Transmission



Sept. 4, 1928.

P. L. TENNEY TRANSMI S S ION Filed June 16, 1926 2 Sheets-Sheet 1 Sept. 4, 1928. 1,682,999

7 P. L. TENNEY v mmsmssxpn Filed June 1 6, 1926 2 Sheets-Sheet 2 A 4 LM gwuentoz l atented Sept. 4, 1928.

UNITED STATES PERRY L. N 351?? GE MUNCIE. ENBIANA, ASSIGNOR TO GENERAL'MOTORS CORPORA- TIGN, 0F DETROIT, MICHIGAN, A CORPORATION OF DELAWARE.

TBANSMISSiON.

Application filed June 16, 1926. Serial No. 116 381.

This invention relates to a changed speed gearing. lt has been arranged particularly for use on motor vehicles but-its use is of course not restricted to that single application.

It is an object of the inventionto provide novel shifter forks having very long bearinsrs. Specifically the long bearings of the fork is obtained by making use of a single rail fxedlypositioned between the two forks and by providing a bearing between each fork member and the side wall of the gear casingrover. By this means the leakage around the ends of the usual sliding rods is avoided.

A further obiect the attainment of which is made possible by the above referred to construction, is the completely enclosed spring detent for the fork.

A still futher object is an improved interlock. -The invention also has as'an o 'iject the avoidance of noise in the act of shifting gears, this being accomplished by s acing the throat of the fork from the groove of the gear.

In the drawing; which shows one specific embodiment of the invention:

Figure 1 shows in longitudinal section a transmi sion housing incorporating the subjcct i'i'iatter of the invention.

F gure 2 is a top plan view looking down upon the shifting forks.

Fi 'ure 3 is a transverse section.

l igure 4; is a section on the line 44 of Figure 2. 7

Referring by reference characters to the drawing. numeral 1 represents a transmishousing. This housing has acover 3 which is secured to the housing in any convenient manner. Entering from the .ront is the clutch driven shaft 4 and a transmission shatf 5, driven by shaft 4. is used to deliver the power of the motor to the rear axle (not shown). The gear shift housing has bearings 7 for shafts e and 5. On shaft i is a driving gear 9 to which may be clutched clutch gear element 11 slidable on shaft 5 for direct drive. For

reducing speed and reverse driving there purpose of effecting driving engagement. Gear 21 operates through reverse idler (not shown) to drive gear 23 and shaft 5. No novelty is alleged for this gearing system. If desired, a transmission brake 25 may be applied to the driven shaft.

ithin the cover of the casing is fixed, in a longitudinal position. a single rail 27. preferably circular in section. This rail may be removably held in positionby a set screw 29. The gears 11- and 23 have grooves formed by the face of the gears and by flanges 24., in which grooves are positioned the semicircular forked portions 31 of the shifting members These forks are extended up- \vardly from'their throat portions to form long sliding heads 35. On the adjacent sides of the heads are longitudinal grooves 37 engaging opposite sides of therail 27, thereby forming a long bearing surface. On the side of each head 35 opposite the groove 37 is atapered wall 39 engaging a similar shaped wall 41' formed on the cover 3. By means of, the rail and the tapered wall of the cover a very substantial guide is provided for the moving shifter fork.

Upon the outer walls of the heads of the forks are notches or grooves 51 for engaging spring actuated detents 53, the springs 55 actuating the detents, being shown in Figure 3. By this arrangement it is seen that the spring actuated detents are fully enclosed in the wall of the cover, and that they engage perpendicularly the tapered wall of the forks. The angular position of the axis of these detents is such that the holes to receive the detents may be conveniently bored from the bottom of the cover.

The construction already described affords very convenient and exceedingly simple means for providing the. interlock between the shifter forks. An annular groove 57 is formed in each head 35 and the grooves are so positioned that they lie opposite to each other when the two shifter forks are in neutral position. A transverse aperture is made in the rail 27 and located in this aperture is a pin 59; The ends of the pin are of tapered rounded shape and the length of the pin is slightly greater than the diameter of the rail, Bythis COIlStIllClllOIlyWllGIl both forks are in neutral the pin 59 may project into either'one of the annular grooves of the heads 35. If now, one of the forks is moved to any other position, the pin auto maticallvlocks the other fork from movement relative to the rail. This construction is obviously extremely simple and requires no springs or other parts which may become worn or interfere with the operation of the gear shift; 7

From Figure 2 it will be seen that when the forks are in neutral position there are oppositely positioned semi-circular grooves 61 positioned in, alignment for engagement by a locked bolt 63 of a lock member 65;

' The locking bolt is normally for engagement with the end of the shift {lever 71 This shift lever passes through the .top of the cover where it is given a universal mounting, as by a cup 73 engaging semispherical surface 75' formed on the cover.

7 A spring 7 7 is positioned bet-ween a cap memthatthe throat of "the fork is shaped soas not to come into contact with the bottom of the groove of the gear, thereby making the operation almost noiseless. The' provision of the single rail between the two shifter forks affords the possibillty of an extremely 1. A gear shifting device comprising a gear casing including a cover, a fixed rail,

a shifter fork having along sliding bearing" with the casing cover on one side, and with said rail on the other side, the plane of the bearing between the casing cover and fork vbeing at an acute angle to theplane 'of the lower surface of the cover. is p 2; Combination of elements enumerated in claim 1 together with a spring pressed detent in'said cover its longitudinalaxis being perpendicular to the plane of the bearing surface and radially disposedwith reference to said rail. w

3. A gear shifting device comprising a gear casing having oposite walls, a guide rail between said-walls, oppositelydisposed fork members, saidfoi'k members slidably engaging the casing walls and having elongated recesses on their adjacent sides to engage the guide rail. I 4. A gear shifting device comprising a gear easing, a fixed guide rail substantially circular in cross section, oppositely disposed" fork members slidably engaging the walls of the'casing and having-ontheir adjacent site sides of said guide rail.

sides elongated grooves slidable upon oppov In testimony whereof I aflix mv signature.

PERRY L, TEN'NEY. 

